AMD Phenom II X4 940 Black Edition [Review]

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AMD Phenom II X4 940 Black Edition [Review]

Roydon Cerejo, Mar 05, 2009 1800 hrs IST

AMD's second take with the Phenom shows promise as we take up their flagship CPU for testing

Good performance, unlocked multiplier, overclocks easily, works with existing AM2+ motherboards

A bit pricey, needs high voltage to overclock beyond 3.6GHz, will not work on AM3 motherboards

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What's new in Phenom II?

Let me make it clear that the Phenom II is not a brand new processor architecturally but simply a die shrink from 65nm to 45nm fabrication process along with a couple of tweaks thrown in. So, instead of improving/changing anything, AMD has just shrunk the die size to rectify the heat issues and power consumption. Thanks to this, AMD was able to increase the level of L3 cache all the way to 6MB instead of just the 2MB limit as seen on the older Phenoms. This itself should improve the performance of memory intensive applications.

What you see above is a quick look at the specifications of the new Phenom II processors. Note that these are the only two based on the AM2+ socket, while all other Phenom IIs will be using the new AM3 platform and will eventually shift to DDR3.

What about the AM3 platform?
Socket AM2 followed quickly on the heels of Socket 939 and eventually replaced it completely. This new socket had 940 pins instead of 939 and all the AthlonX2s were based on this. Once the Phenoms were launched, they were designed to run on the newer AM2+ platform, which was again achievable by a simple BIOS upgrade.

So what's the big deal with this new platform? Well, AM3 motherboards, which will soon be launched, will support DDR3 RAM only and hence will require an AM3 compatible processor too. Also, AM3 motherboards will have 938 pins so AM2+ processors won't fit. But if you have an AM2+ motherboard, you should be able to use an AM3 processor since it is compatible (you may need a BIOS update though).

But I thought AM3 processors work with DDR3 memory? The secret lies in the design. AM3 processors have both DDR2 and DDR3 memory controllers embedded, making them compatible with both types of motherboards. So, if you already have an existing AM2+ motherboard, you'll be able to use the latest AM3 Phenom II processors, and later, if need be, just switch over to a AM3 motherboard with a DDR3 RAM while retaining the same processor. This is a fantastic move by AMD because you can get yourself an AM3 processor, and once the prices of DDR3 memory falls, make the switch for better performance.